Chemically amplified positive resist compositions include a resin component that exhibits increased alkali solubility under the action of acid, and an acid generator that generates acid on exposure, and a variety of these compositions have been proposed (see the patent references 1 and 2, listed below).
Every year the resolution demanded of these chemically amplified positive resist compositions continues to increase. Furthermore, resist patterns of favorable shape, in which, for example, the side walls of the resist pattern exhibit a high degree of verticalness, are also being demanded.
However, as the requirements for improved resolution and resist patterns of better shape become ever more demanding, conventional chemically amplified positive resist compositions become unable to satisfactorily meet those requirements.
Furthermore, conventionally, in the formation of magnetic heads and the like, a magnetic film is laminated on top of a substrate, and a process is then conducted for providing a resist layer on top of the magnetic film and forming a resist pattern.
In some cases, if required, a metallic oxidation prevention film that prevents oxidation of the magnetic film may be first laminated on top of the magnetic film, and the resist layer then formed on top of this oxidation prevention film.
The magnetic film uses a material containing one or more metals selected from iron, cobalt and nickel as its primary component.
Furthermore, the oxidation prevention film uses a material containing at least one of tantalum and aluminum oxide (Al2O3) as its primary component.
However, when a conventional positive resist composition is used to form a resist layer on top of a magnetic film, or on top of a metallic oxidation prevention film provided on top of a magnetic film, a pattern of favorable shape is not always obtainable, due to problems such as the so-called tailing phenomenon, where the region near the interface between the resist pattern and the magnetic film or the oxidation prevention film becomes tapered, or the so-called undercutting phenomenon, where, in contrast, the region near the interface between the pattern and the magnetic film or the oxidation prevention film narrows, causing undercutting of the inside of the pattern.
(Patent Reference 1)
    Japanese Unexamined Patent Application, First Publication No. Hei 11-305442(Patent Reference 2)    Japanese Unexamined Patent Application, First Publication No. Hei 8-15864(Patent Reference 3)    Japanese Unexamined Patent Application, First Publication No. Hei 11-339223